How does married life change after having a baby? Would like to be mentally prepared for this and not taken by surprise!

Before having a baby, you get to do whatever you want. You can watch a movie whenever you feel like it, or go shopping together. Basically, I would say that there isn't TOO much of a difference between dating and married life apart from the legal and financial issues. However, there is a huge jump when a baby is added into the equation. Especially if you are breastfeeding and cannot leave baby (with a caregiver) at home for more than 2 hours, everything you do has to pander around the baby's schedule. Obviously this means there has to be a deeper understanding and acceptance that the baby's needs come first. The frequency of sex will definitely decrease in the first few months after giving birth. There will also be more issues to argue about. Having a baby is a test of the strength of your partnership. It's a lifelong project.